Dogs are not only considered man's best friend because they make great companions.

Many of these four-legged friends are helping U.S. armed forces in battle, fighting crime next to police officers, and even comforting people who've suffered a disaster.

Helping Broken Bodies

Service dogs meet a person's physical needs, and sometimes emotional needs, in ways that traditional medicine can not. Their constant companionship can help the disabled manage everyday life.

Mark Hagen needs a service dog because he has a dangerous type of diabetes.

"In the last couple of years, I have become what's known as hypoglycemic unaware," he said. "Which means I can't sense what my blood sugar's doing."

"So I can't tell if it's high, I can't tell if it's low, so I will drop into an unsafe area where I can't help myself any longer," he explained.

Hagen's service dog, Chloe, is so well trained that she can actually smell if Mark's blood sugar is too high or too low.

Chloe will touch him with her paws - an alarm to Mark but is hardly noticed by anyone else.

Training for Service

Scott Smith, who trained Chloe at Tidewater K9 Academy in Chesapeake, Va., said it's important that the dogs behave in a subtle manner.

"One of the things that everyone wants to make sure of is that when the service dog is out in public, it's well behaved, well mannered and it's not being disruptive to the environment or to the people around it," he said.

It took nine months to transform Chloe from a rambunctious, untrained pooch into the trustworthy service dog she is today.

Mark Hackathorn owns Tidewater K9 Academy, and has been training service dogs for 30 years.

It's a winning situation for the him, the clients, and even the dogs, because many of the dogs are rescues.

Hackathorn searches Craigslist and the newspaper for dogs whose families no longer want them. He trains all breeds, but is partial to poodle mixes because many are hypoallergenic.

He loves what he does, except saying goodbye.

"It's a little sad sometimes because we're working with the dogs so closely," he said. "But I realize that these dogs were really given to me, through however they got to me, to then get to people to help them save their life."

Helping Wounded Warriors

Service dogs vastly improve the lives of people who are blind, epileptic, deaf, or those at risk for heart attacks, stroke, and even panic attacks.

Luis Carlos Montalvan, a war veteran, uses a service dog named Tuesday because Luis suffers from Post Traumatic Stress Disorder.

"He's like a guardian angel," Montalvan said. "God sends beings like Tuesday into our lives to help us with our journey."

Luis returned from Iraq with both physical and emotional wounds that left him afraid to leave his apartment.

In his book, Until Tuesday, Montalvan describes how God is using Tuesday to heal him.

"In crowded places, which can remind me of riots and difficult situations in Iraq, I can literally ask him to act as a buffer between a group of people and myself," the war vet explained.

"He wakes me up from nightmares, he's been trained to do that. He helps me walk," he said. "I have a spinal condition, so he helps me when I walk, particularly down stairs."

Passing the Test

In addition to service dogs, therapy dogs also bring help and healing. These pets visit people with special needs, like the tiny cancer patients at The Chidren's Hospital of the King's Daughers in Norfolk, Va.

Heather Bamford, an oncology nurse at CHKD, sees first hand the the positive impact therapy dogs have on the kids. She added that scientific research backs that up.

"There are studies that show that people with chronic pain or chronic illnesses do have less stress, less anxiety, lower heart rate, decreased blood pressure, definitely improved mood, when doing pet therapy," Barnford said..

Therapy dogs do not have to be trained nearly as thoroughly as service dogs, but they do need to pass a test.

Mark Hoggard, who owns a service dog, said the test is easier for some dogs than others.

"They have to be able to sit on command, and down on command and stay, and some of the basic obedience," he said.

"And then they do some more advanced stuff with them, like they have to be able to walk by food without gobbling it up and they have to not be distracted," he explained. "We do distraction with wheelchairs and walkers and things the dog might not see in everyday life."

Therapy for the Soul

In addition to working at hospitals, therapy dogs are also welcome visitors at nursing homes. The residents say holding the dogs makes them feel comfortable and relaxed.

Norma Minnick lives at Sentara Village Nursing Center in Chesapeake, Va. She said spending time with her favorite therapy dog Zoe is often the highlight of her day.

Lorie Johnson

CBN News Medical Reporter

Lorie Johnson reports on the latest information about health and wellness. Since medicine is constantly changing, she makes sure CBN News viewers are up-to-date on what they need to know in order to live a healthy life. Follow Lorie on Twitter @LorieCBN and "like" her at Facebook.com/LorieJohnsonCBN.